Thermal overload relay with reset means



1965 P. T. ANDERSON ET AL 3,

THERMAL OVERLOAD RELAY WITH RESET MEANS IOI WITNESSES INVENTORS Paul T.Anderson 8 ?4 JBoYmes 8. Ramsey J yummy a. M

ATTORNEY 1965 P. T. ANDERSON ET AL 3,213,243

THERMAL OVERLOAD RELAY WITH RESET MEANS Filed June 21, 1962 3Sheets-Sheet 2 0 O m [3 d1 5 '8 g .E O u.

Fig. 3

1955 P. T. ANDERSON ET AL 3,213,243

THERMAL OVERLQAD RELAY WITH RESET MEANS 3 Sheets-Sheet 5 Filed June 21,1962 mo mk howe r7 United States Patent 3,213,243 THERMAL OVERLOAD RELAYWITH RESET MEANS Paul T. Anderson and James B. Ramsey, BrightonTownship, Beaver County, Pa., assignors to Westinghouse ElectricCorporation, East Pittsburgh, Pa., a corporation of Pennsylvania FiledJune 21, 1962, Ser. No. 204,282 7 Claims. (Cl. 200-122) This inventionrelates generally to electric control devices and more particularly toambient temperature compensated thermal overload relays.

An object of this invention is to provide an improved electric controldevice for controlling either a normally open or a normally closedcircuit.

Another object of this invention is to provide a thermal overload relaywith improved means for resetting the relay after the relay has beenautomatically actuated.

Another object of this invention is to provide an improved thermaloverload relay that is actuated from an initial position wherein a firstset of two contacts is closed,- to an actuated position to open thefirst set of contacts and close a second set of contacts, which relay isreadily arranged to provide either manual or automatic operation back tothe initial position.

A further object of this invention is to provide a relay in accordancewith the immediately preceding object wherein a movable contact arm iscommon to both sets of contacts and the relay can be changed to controleither a normally open or normally closed circuit merely by changing theexternal connection.

In accordance with another embodiment of this invention, an object is toprovide an improved relay for controlling two separate andvoltage-independent circuits.

A further object of this invention is to provide a thermal overloadrelay with improved means for adjusting the operating characteristics ofthe relay.

Another object of this invention is to provide an improved relay withimproved means providing a visual indication that the relay has beenactuated.

The invention both as to structure and operation, together withadditional objects and advantages thereof, will be best understood froma study of the following detailed description of different embodimentsthereof when the study is made in conjunction with the accompanyingdrawings.

In said drawings:

FIGURE 1 is an end elevation-a1 view of a relay constructed inaccordance with principles of this invention;

FIG. 2 is a side elevational view, with the front cover removed, of therelay seen in FIG. 1;

FIG. 3 is an end elevational view of the relay seen in FIG. 1 taken fromthe end opposite the end shown in FIG. 1;

FIG. 4 is a side elevational view, with the back cover removed, of therelay seen in FIGS. 1-3;

FIG. 5 is an elevational view of the stationary contact structure seenin FIG. 2;

FIG. '6 is an elevational view of the movable contact structure seen inFIGS. 2 and 4;

FIG. 7 is a view similar to FIG. 2 of a relay representing a differentembodiment of the invention; and,

FIG. 8 is .a view similar to FIG. 4 of the relay shown in FIG. 7.

Referring to the drawings, and particularly to FIGS. 1-6, there is showntherein an electric control device 3 of the type known in the art as anambient temperature compensating overload relay. The relay 3 comprises ahousing 5 of molded insulating material that comprises a central part 7,a front cover 9 and a back cover 11.

The parts 7, 9 and 11 of the housing 5 are secured together by means ofthree rivets 13. The housing 5 is supported on a suitable base 15. Acontrol mechanism 17 is supported inside the housing 5 and comprises anactuating bimetal member 19 (FIG. 2) that is attached at one end to asupport 21. The support 21 is pivotally mounted in the housing 5 bymeans of a pivot pin 23. A spring 25 biases the support 21 and bimeta-l.19 in a counterclockwise (FIG. 2) direction about the pivot 23, whichmovement is limited by engagement of the support 21 with an adjustingscrew 24. An insulating knob 27 is disposed at the outer end of theadjusting screw 25 to provide for manual operation of the screw 25 inorder to permit adjustment of the position of the support member 21 andactuating :bimetal 19 within the housing. Surfaces 29 (FIG. 1) areprovided on the adjusting knob 27 to engage opposite sides of a stop 31in order to limit movement of the adjusting knob 27 to preventoveradjustment of the initial position of the actuating bimetal 19 andsupport 21.

The free end of the bimetal 19 engages one end of an insulating thrusttransmitting member 33 that is slidably supported in the housing 5 in atrack 35 molded integral with the housing. The other end of the thrusttransmitting member 33 engages the free end of a compensating bimetalmember 37 that is fixed at its other end to a support 39. The support 39is pivotally supported in the housing 5 on a pivot pin 41.

An overcenter spring 43 (FIG. 2) is supported, at one end, in an openingin the support 39, and, at the other end, in an opening 4 5 (FIG. 6) ina generally U-shaped part 47 of a movable cont-act structure 49. The legportions 51 (FIG. 6) of the movable contact arm 47, engage in suitablenotches in a terminal strip 53 (FIG. 2) to pivotally support the movablecontact arm 47 on the terminal 53. Contacts 55 and 57 (FIGS. 2 and '6)are secured to opposite sides of the movable contact arm 47. An extendedportion 59 of one leg of the movable contact arm 47 serves as anindicator that, as will be hereinafter specifically described, protrudesfrom the housing 5 when the relay is set for a hand resetting operationand the relay has been actuated by operation of the control mechanism17.

In operation, the movable contact arm 47 cooperates with a relativelystationary contact structure 61 (FIGS. 2 and 5). The relativelystationary contact structure 61 comprises a resilient contact arm 63that is fixedly supported on a terminal strip 65. A contact 67 issuitably secured to the contact arm 63.

In operation, the movable contact arm 47 also cooperates with anotherrelatively stationary contact structure 71 (FIGS. 2 and 4). Therelatively stationary contact structure 71 comprises a contact arm 73that is secured to a conducting tab 75 (FIGS. 2 and 4) which tab 75 issuitably secured in the housing and is connected to a terminal strip 77.A contact 79 (FIGS. 2 and 4) is secured to the free end of the contactarm 73. An extension 81 is provided on the contact arm 73 to permitresetting of the relay in a manner to be hereinafter specificallydescribed.

Terminal screws 85 are provided at the outer ends of the conductingstrips 53, 65 and 77 to permit connection of the relay in circuits to becontrolled by the relay 3.

The controlling circuit of the relay 3 comprises a conducting strip 87(FIG. 2) having a terminal connector 89 at its outer end, and aconducting strip 91 having a terminal connector 93 at its outer end. Theconducting strips 87 and 91 are suitably supported in molded formationsin the housing 5. A replaceable heater member 95 is supported at oneend, on the conducting strip 87 by means of a screw 97, and at the otherend, on the conducting strip 91 by means of a screw 99.

An insulating reset rod 101 having a notch 193 (FIG. 4) thereinprotrudes from the housing 5. An adjusting spring 105 has one endthereof disposed in the notch 193, and the other end protruding from thehousing 5. The external end of the adjusting spring 1115 can be disposedeither in a slot 109 or a slot 11, which slots are formed in the moldedhousing 5 during the molding operation thereof. When the spring 1115 isin the slot 111, the relay is set for a hand resetting operation, andwhen the spring 105 is in the slot 109 the relay is set for an automaticresetting operation.

The operation of the relay 3 is as follows:

The relay is shown in FIGS. l-4 in the actuated position with the spring105 (FIG. 4) being in the handreset position. When the parts are in theposition seen, the conotact 57 of the movable contact structure 49engages the contact 79 of the relatively stationary contact structure71. The relay is reset back to an initial position by manual depressionof the reset rod 191 during which movement a shoulder portion 113 (FIG.4) of the rod 101 engages the extension 81 of the relatively stationarycontact arm 73 moving the resilient contact arm 73 and the movablecontact arm 47 counterclockwise (FIG. 2) to move the contact arm 47 andspring 43 to a position where the spring 43 is overcenter with respectto the contact arm 47 whereupon the spring 43 operates to move thecontact arm 47 into engagement with the contact 67 flexing the resilientcontact arm 63 to the right (FIG. 2) until the back portion of thecontact 67 engages the terminal 65. The parts then remain in the initialposition until the relay is actuated.

The controlling circuit of the relay 3 passes from the terminal strip 87(FIG. 2) through the heater 95 to the terminal strip 91. When the partsare in an initial position wherein the contact 55 of the movable contactarm 47 engages the relatively stationary contact 67, and an overloadcurrent passes through the controlling circuit, heat from the heater 95operates to flex the bimetal 19 to actuate the relay. The high expansionside of the bimetal 19 is on the left (FIG. 2) and, when the bimetal isheated, the lower or free end of the actuating bimetal 19 moves to theright. This movement of the bimetal 19 operates, through the thrusttransmitting member 33, to move the compensating bimetal 37 and supportmember 39 in a counterclockwise (FIG. 2) direction about the pivot 41.During this movement, the spring 43 is carried to an overcenter positionto the left of the movable contact arm 47 whereupon the spring 43operates with a snap action to move the movable contact arm 47 into theposition seen in FIGS. 2 and 4 in which position the contact 57 of themovable contact arm 47 engages the relatively stationary contact 79 onthe contact arm 71. In the position seen in FIGS. 2 and 4, the spring 43is so positioned that it holds the movable contact arm 47 in theactuated position about the pivot 51 and the compensating bimetal 37 andsupport 39 in the actuated position about the pivot 41. Thereafter, theparts can be reset to the initial position in the same mannerhereinbefore described.

When it is desired to have the relay 3 reset automatically after it hasbeen actuated, the free end of the spring 105 (FIG. 4) is removed fromthe slot 111 and moved up into the slot 109. This pivots the spring 105about a molded pivot 119 during which movement of the inner end of thespring 195 operates to move the reset rod 191 to a lower position. Whenthe reset rod 101 is in the lower position, and the relay is actuated bymeans of an overload current, the movable contact arm 47 will move onlyto the position shown in dotted lines in FIG. 2. This actuated movementis so limited by engagement of the portion 81 of the contact arm 73 withthe shoulder portion 113 (FIG. 4) of the reset rod 101. When the partsare in this actuated position, the spring 43 is overcenter with respectto the contact arm 47 so that the spring 43 maintains the contact arm inthe actuated position; but the spring 43 still biases the compensatingbimetal 37 and support 39 clockwise about the pivot 41, which clockwisemovement is prevented because of the engagement of the compensatingbimetal 37 with the thrust transmitting member 33 which member engagesthe lower end of the actuating bimetal 19. When the bimetal 19 cools andthe lower end thereof moves back to the left (FIG. 2) to no longerprevent this clockwise movement of the bimetal 37 and support 39, thespring 43 automatically moves the bimetal 37 and support 39 clockwise,whereupon the spring 43 moves overcenter to the right (FIG. 2) of thecontact arm 47 to thereby snap the contact arm 47 back to the initialposition in which position the contact 55 engages the contact 67. Theparts will thereafter remain in the initial position until the relay isagain actuated by an overload current.

The bimetal 37 compensates for movement of the actuating bimetal 19 inresponse to changes in ambient temperature. The high expansion side ofthe compensating bimetal 37 is on the left as seen in FIG. 2 so that thecompensating bimetal 37 will flex in the same direction as the actuatingbimetal 19. Thus, when the bimetal 19 flexes to the right (FIG. 2) inresponse to a rise in the ambient temperature, the compensating bimetal37 will flex an equal amount to the right without affecting anysignificant movement of the support 39, spring 43 and contact arm 47.Thereafter, if the ambient temperature drops, and the actuating bimetal19 moves back to the left, the compensating bimetal 37 will move back tothe left without affecting any significant movement of the support 39,spring 43 and contact arm 47. Thus, the compensating bimetal 37compensates for movement of the actuating bimetal 19 in response tochanges in ambient temperature.

As is seen in FIG. 2, the relay 3 can be connected to control either anormally open or a normally closed circuit. When it is desired tocontrol a normally closed circuit, the leads of the controlled circuitare connected to the common terminal strip 53 and to the normally closedterminal strip 65. When so connected, and when the relay is in theinitial or normally closed position, the controlled circuit passesthrough the common conducting strip 53, the movable contact arm 47, thecontact '55, the contact 67, the relatively stationary contact arm 63 tothe conducting strip 65. When the relay is actuated by an overloadcurrent through the conductor 87, heater and conductor 91, the partswill move to the actuated or open circuit position seen in FIG. 2.Thereafter, the relay can be reset either automatically or manually tothe initial or closed circuit position in the manner hereinbeforedescribed.

If it is desired to control a normally open circuit by means of therelay 3, leads are connected to the common conducting strip 53 and thenormally open conducting strip 77. Thus, the initial position of therelay would be normally open and upon actuation of the relay to theposition seen in FIG. 2, a circuit would be made from the conductingstrip 53 through the movable contact arm 47, the contact 57, the contact79, the contact arm 73, the conducting tab 75 to the conducting strip77. The circuit is opened when the relay is reset either manually orautomatically.

As is seen in FIG. 2, when the relay 3 is operated to the actuatedposition and the adjusting spring (FIG. 4) is in the hand resetposition, the indicating portion 59 of the movable contact arm 47 movesout through an opening 121 (FIG. 3) in the housing 5 to provide a visualindication that the relay has been actuated. Thereafter, when the relayis reset, the indicator 59 moves back into the housing. With theprovision of the indicator 59 in the relay 3, a worker, looking at anumber of similar relays in a panelboard, can readily seen which, of therelays has tripped and must be manually reset.

A different embodiment of the invention is shown in FIGS. 7 and 8. Therelay shown in FIGS. 7 and 8 is.

similar in many respects to the relay shown in FIGS. 1-4 and, therefore,only new elements are identified by reference characters not found inFIGS. 1-4, whereas other elements which are substantially identical withor equivalent to elements found in FIGS. 1-4 are designated by means ofprimed numbers corresponding to the numbers used in FIGS. l-4.

The controlling circuit of the relay 3 extends from the terminal strip87 through the actuating bimetal 19, the flexible conductor 125 to theconducting strip 91. Thus, the bimetal 19' is heated directly by currentpassing therethrough rather than indirectly by means of a heater as isthe case in the relay 3 seen in FIG. 2. The relay 3' can be used tocontrol two separate circuits which are voltage independent. A first ofthese circuits, which is a normally closed circuit, extends from aterminal strip 127 (FIG. 7) through a conducting tab 129, the movablecontact arm 47', the movable contact 55, the relatively stationarycontact 67', the contact arm 63', to a conducting strip 131. When theparts are in the initial position seen in FIGS. 7 and 8 and the relay 3is thereafter actuated by an overload current passing through thecontrolling circuit, the bimetal 19 flexes to move thethrust-transmitting member 33 to the right FIG. 7) to move thecompensating bimetal 37' and support 39' in a counterclockwise directionabout the pivot 41 to move the spring 43 overcenter whereupon the springoperates to move the movable contact arm 47 clockwise about its pivot 51to open the contacts 55, 67. During this movement, the side of themovable contact arm 47' which is opposite the side that supports thecontact 55', engages an insulating member 132 (FIG. 8) that is slidablysupported in a suitable track in the molded housing part 7; and movesthe member 132 to the right (FIG. 8) during which movement the member132 moves a resilient conducting member 133 to the right to engage acontact 134 with a contact 135. This movement closes a circuit thatextends from a terminal conductor 139, through the resilient conductingmember 133, the contact 134, the contact 135, a resilient conductingstrip 141 to a terminal conductor 143. When the bimetal 19 thereaftercools and moves back to the original position in which is appears inFIG. 7, the circuit breaker is reset (either automatically or manuallydepending upon whether the outer end of the spring 105 is positioned inthe slot 109' or the slot 111), back to the initial position seen inFIGS. 7 and 8 in which position the contacts 55, 67' of the normallyclosed circuit are closed and the contacts 133, 135 of the normally opencircuit are open. As is best seen in FIG. 8, if the spring 105' is setfor a hand-resetting operation and the reset rod 101 is pushed down, acam surface 145 on the reset rod 101' engages the conducting strip 141moving this member and the resilient conducting strip 133 to the left(FIG. 8) to move the insulating member 132 to the left to move themovable contact arm 47' and the movable contact 55 to the left (FIG. 8)to a position where the spring 43 (FIG. 7) is overcenter with respect tothe contact arm 47' and operates to move the movable contact arm 47'back to the initial position with a snap action. As is seeri in FIG. 8,the conducting strips 133 and 141 are resilient so that they willautomatically move back to the initial position seen in FIG. 8 after therelay has been actuated and reset.

If the free end of the spring 105' (FIG. 8) is moved to the slot 109',the relay will be set to automatically reset after it has been actuated.In this case the reset rod 101' will be moved down to bias the conductor141 to the left to limit movement of the conductor 133, the member 132,the contact arm 47' and the spring 43. When the relay has been actuated,the parts will be so positioned that the spring 43 will operateautomatically, in the same manner hereinbefore described with relationto the relay seen in FIGS. 1-4, to move the contact arm 6 47' back tothe intial position seen in FIGS. 7 and 8 when the bimetal 19' cools andreturns to the initial position.

As can be seen in FIGS, 7 and 8, the two circuits (one a normally closedcircuit from the conductor 127 to the conductor 131 and the other anormally open circuit from the conductor 139 to the conductor 143) arevoltage independent in that they are separate circuits completelyinsulated from each other. The relay 3' can be connected to control onlyone of the circuits, or it can be connected to simultaneously controlboth of the circuits.

Improved means are provided for adjusting the rating of the relay 3'. Asis seen in FIG. '7, an adjusting screw 147 having an insulating knob 149at its outer end is mounted in a tapped opening in the conducting strip131. Thus, this member can be rotated to move the flexible relativelystationary contact member 63' either to the left or to the right as seenin FIG. 7 to adjust the normal or initial position of the movablecontact arm 47. This adjustment will control the rating of the relay bycontrolling the amount of work of the actuating bimetal 19' that isnecessary in order to effect movement of the overcenter spring 43 to anovercenter position. Thus, the relay will be actuated upon theoccurrence of more or less overload current depending on whether theknob 149 is rotated to pivot the contact arm 47' counterclockwise (FIG.7) or clockwise respectively. In order to provide that the relay 3'cannot be over-adjusted to a position where nuisance tripping wouldoccur or where a severe overload current could damage the parts, a stopportion 151 is molded integral with the housing part 7' to limitmovement of the adjusting knob 149 in both directions.

From the foregoing, it can be understood that there is provided by thisinvention an improved thermal overload relay that can be connected tocontrol either a normally open or a normally closed circuit. The relayis manually reset by operation of a reset rod to actuate a resilientstationary contact structure to move a contact structure and spring to aposition where the spring is overcenter with respect to the contactstructure whereupon the spring operates to move the contact structure toa normal or initial position. The relay is automatically reset when thereset rod is positioned to position the resilient stationary contactstructure and movable contact structure so that when the thermal meanscools the spring will automatically be in an overcenter position toautomatically move the movable contact structure to the initialposition. In another embodiment of the invention, there is provided animproved overload relay that can be connected to control either anormally open circuit or a normally closed circuit, or to simultaneouslycontrol both of said circuits which circuits are voltage-independent.The invention also provides improved indicating means for indicatingthat a relay has been actuated by means of an overload currentcondition. The invention also provides improved means for adjusting athermal overload relay to vary the rating of the relay.

While the invention has been disclosed in accordance with the provisionsof the patent statutes, it is to be understood that various changes andmodifications may be made without departing from the spirit and scope ofthe invention.

We claim as our invention:

1. An electric control device comprising, in combination, a housing, afirst relatively stationary contact supported in said housing, a movablecontact structure sup ported in said housing in an initial positionengaging said first relatively stationary contact, a second relativelystationary contact supported in said housing, current responsive meanssupported in said housing and operable upon the occurrence of certaincurrent conditions to automatically effect movement of said movablecontact structure to an actuated position out of engagement with saidfirst relatively stationary contact and in engagement with said secondrelatively stationary contact, and reset means supported on said housingand operable to actuate said second relatively stationary contact toeflfect movement of said movable contact structure back to said initialposition.

2. An electric control device comprising, in combination, a housing, afirst relatively stationary contact supported in said housing, a movablecontact structure supported in said housing in an initial positionengaging said first relatively stationary contact, a second relativelystationary contact supported in said housing, overcenter spring meanssupported in said housing, bimetal means supported in said housing, saidbimetal means being heated upon the occurrence of certain currentconditions and moving to operate said overcenter spring means to effectmovement of said movable contact structure to an actuated position outof engagement with said first relatively stationary contact and inengagement with said second relatively stationary contact, reset meansextending from said housing and being manually operable tomove saidsecond relatively stationary contact to operate said overcenter springmeans to thereby effect movement of said movable contact structure backto said initial position.

3. An electric control device comprising, in combination, a housing, afirst relatively stationary contact supported in said housing, a movablecontact structure in an initial position engaging said first relativelystationary contact, a second relatively stationary contact supported insaid housing and comprising a resilient member having a second contactthereon, overcenter spring means supported in said housing, currentresponsive means supported in said housing and operating upon theoccurrence of certain current conditions to relatively position saidovercenter spring means to effect movement of said movable contactstructure to an actuated position out of engagement with said firstrelatively stationary contact and in engagement with said secondcontact, reset means extending from said housing and being manuallyoperable to flex said resilient member to relatively position saidovercenter spring means to thereby effect movement of said movablecontact structure from said actuated position to said initial position.

4. An electric control device comprising, in combination, a housing, afirst relatively stationary contact supported in said housing, a movablecontact structure supported in said housing in an initial positionengaging said first relatively stationary contact, a second relativelystationary contact supported in said housing, bimetal means supported insaid housing, said bimetal means being heated upon the occurrence ofcertain current conditions and deflecting to effect movement of saidmovable contact structure to an actuated position away from said firstrelatively stationary contact and in engagement with said secondrelatively stationary contact, reset means extending from said housing,said reset means being in a first position to position said secondrelatively stationary contact and said movable contact structure afteractuation of said movable contact structure so that when said bimetalcools said movable contact structure will be automatically moved back tosaid initial position, means for positioning said reset means in asecond position to thereby position said second relatively stationarycontact and said movable contact structure after actuation of saidmovable contact structure so that when said bimetal cools said movablecontact structure will remain in engagement with said second relativelystationary contact, and said reset means when in said second positionand after actuation of said movable contact structure being movable tomove said first relatively stationary contact to thereby effect movementof said movable contact structure back to said initial position.

5. An electric control device comprising, in combination, a housing, afirst relatively stationary contact supported in said housing, a movablecontact structure supported in said housing in an initial poistionengaging said first relatively stationary contact, a second relativelystationary contact supported in said housing, overcenter spring meanssupported in said housing, bimetal means supported in said housing, saidbimetal means being heated upon the occurrence of certain currentconditions and deflecting to relatively position said overcenter springmeans to effect movement of said movable contact structure to anactuated position in which position said movable contact structure isout of engagement with said first relatively stationary contact and inengagement with said second relatively stationary contact, reset meansextending from said housing said reset means being in a first positionto effect automatic movement of said movable contact structure from saidactuated position to said initial position when said bimetal cools,means for positioning said reset means in a second position so that saidmovable contact structure will remain in said actuated position whensaid bimetal cools, and when said reset means is in said secondposition, said reset means being manually movable to move said firstrelatively stationary contact to relatively position said overcenterspring means to thereby effect movement of said movable contactstructure from said actuated position to said initial position.

6. An electric control device comprising, in combination, a housing, afirst relatively stationary contact supported in said housing, a movablecontact structure sup ported in said housing in an initial positionengaging said first relatively stationary contact, a second relativelystationary contact supported in said housing, overcenter spring meanssupported in said housing, a bimetal member supported in said housing,said bimetal member being heated upon the occurrence of certain currentconditions and deflecting to operate said overcenter spring means toeflfect movement of said movable contact structure from said initialposition to an actuated position in which actuated position said movablecontact structure is out of engagement with said first relativelystationary contact and in engagement with said second relativelystationary contact, reset means extending from said housing, said resetmeans being in a first position to position said movable contactstructure when said movable contact structure is in said actuatedposition so that when said bimetal cools said overcenter spring meanswill operate automatically to move said movable contact structure backto said initial position, said reset means being settable in a secondposition to thereby position said movable contact structure when saidmovable contact structure is in said actuated position so that when saidbimetal cools said movable contact structure will remain in saidactuated position, and when said reset means is in said second positionsaid reset means being manually movable to move said first relativelystationary contact to operate said overcenter spring means to therebyeflect movement of said movable contact structure from said actuatedposition to said initial position, bimetal means supported in saidhousing and operating to compensate for movement of said bimetal memberin response to changes in ambient temperature.

7. An electric control device comprising, in combination, a housing, arelatively stationary contact supported in said housing, a movablecontact structure supported in said housing in an initial positionengaging said relatively stationary contact, a relatively stationaryflexible contact structure supported in said housing, overcenter springmeans supported in said housing, an actuating bimetal member supportedin said housing, a compensating bimetal member supported in saidhousing, means operatively connecting said actuating bimetal member withsaid compensating bimetal member, said actuating bimetal member beingheated upon the occurrence of certain current conditions and deflectingto move said compensating bimetal member to operate said overcenterspring means to effect movement of said movable structure from saidinitial position to an actuated position in which actuated position saidmovable contact structure is out of engagement with said relativelystationary contact and in engagement with said flexible contactstructure, reset means extending from said housing, said reset meansbeing in a first position to position said flexible contact structure tothereby position said movable contact structure when said movablecontact structure is in an actuated position so that when said actuatingbimetal member cools said overcenter spring means will operateautomatically to effect movement of said movable contact structure fromsaid actuated position to said initial position, means for positioningsaid reset means in a second position to position said flexible contactstructure to thereby position said movable contact structure when saidmovable contact structure is actuated so that when said actuatingbimetal cools said movable contact structure will remain in saidactuated position, and said reset means when in said second positionbeing manually movable to move said relatively stationary flexiblecontact structure to thereby effect movement of said movable contact 210 structure from said actuated position to said initial position.

References Cited by the Examiner UNITED STATES PATENTS 2,452,508 10/48Ulanet 200-139 2,513,748 7/50 Schaefer 200-122 2,557,810 6/51 Bletz200-139 2,558,219 6/51 Kohl 200-67 2,792,466 5/57 Raney 200-6'72,831,943 4/58 Ramsey et al. 200-113 2,854,555 9/58 Edmunds 200-1672,897,319 7/59 Wolff 200-122 2,897,326 7/59 DeVito 200-167 2,908,78610/59 Schleicher 200-116 2,942,081 6/ 60 Ramsey et a1. 200-113 2,980,7794/61 Hickel et a1. 200-113 0 BERNARD A. GILHEANY, Primary Examiner.

1. AN ELECTRIC CONTROL DEVICE COMPRISING, IN COMBINATION, A HOUSING, AFIRST RELATIVELY STATIONARY CONTACT SUPPORTED IN SAID HOUSING, A MOVABLYCONTACT STRUCTURE SUPPORTED IN SAID HOUSING IN AN INITIAL POSITIONENGAGING SAID FIRST RELATIVELY STATIONARY CONTACT, A SECOND RELATIVELYSTATIONARY CONTACT SUPPORTED IN SAID HOUSING, CURRENT RESPONSIVE MEANSSUPPORTED IN SAID HOUSING AND OPERABLE UPON THE OCCURRENCE OF CERTAINCURRENT CONDITIONS TO AUTOMATICALLY EFFECT MOVEMENT OF SAID MOVABLECONTACT STRUCTURE TO AN ACTUATED POSITION OUT OF ENGAGEMENT WITH SAIDFIRST RELATIVELY STATIONARY CONTACT AND IN ENGAGEMENT WITH SAID SECONDRELATIVELY STATIONARY CONTACT, AND RESET MEANS SUPPORTED ON SAID HOUSINGAND OPERABLE TO ACTUATE SAID SECOND RELATIVELY STATIONARY CONTACT TOEFFECT MOVEMENT OF SAID MOVABLE CONTACT STRUCTURE BACK TO SAID INITIALPOSITION.